Practical uses
- fishing rods and rod blanks (glass builds are valued for a slow, forgiving action);
- snow and driveway markers, flags and delineators;
- tent and awning poles, kite spars and model parts;
- plant, tree and garden stakes;
- antennas, signage and support rods in industry.
| Rod variable | Effect |
|---|---|
| Diameter | Stiffness rises with the fourth power of diameter: a small change has a large effect |
| Solid or hollow | Hollow is lighter for the same stiffness; solid resists crushing (solid vs hollow rods) |
| Fibre and resin | More glass and straight fibres give a stiffer, stronger rod; resin sets weather and fatigue behaviour |
| Taper | A tapered rod flexes progressively, used in fishing rods |
| Finish | Smooth, ground or coloured; coatings protect from UV |
Specifying a rod blank
- Length, butt and tip diameter and taper.
- Action (how it bends) and the load it must carry.
- Solid or tubular, and the wall thickness.
- Finish and colour.
Round-rod details and sizes: solid vs hollow fiberglass rods.
How much will a rod bend? (calculated)
For a solid rod clamped at one end, tip deflection under a tip load is δ = P·L³ / (3·E·I) with I = πd⁴/64. The table uses an assumed E of 40 GPa (a typical order for a solid unidirectional glass rod; the real value depends on glass content), a free length of 0.5 m and a tip load of 1 N.
| Diameter (mm) | I (mm⁴) | Tip deflection (mm) |
|---|---|---|
| 4 | 13 | 83 |
| 6 | 64 | 16 |
| 8 | 201 | 5 |
| 10 | 491 | 2 |
Doubling the diameter reduces deflection about 16 times, which is why a small change in diameter changes the feel of a rod. Large deflections are not linear, so use this only for comparison and ask the maker for tested flex data.
Send us your requirement
Guangdong Haikuo Composite Materials Co., Ltd. (Huizhou, Guangdong) designs pultrusion moulds in-house and produces custom FRP profiles. Send a drawing, a sample or just the application and the environment, and we will tell you what is feasible.
Email: [email protected] | WhatsApp: +86 189 5198 8522